最短路 dijkstra 數組實現

最短路 dijkstra 數組實現

/* Dijkstra數組實現O（N^2）<br />Dijkstra --- 數組實現(在此基礎上可直接改為STL的Queue實現)<br /> g[][] --- 鄰接陣，i 到 j 的初始距離<br />dist[] --- beg到其他點的最近距離<br />path[] --- beg為根展開的樹，記錄父親結點 */<br />#define INF 0x7ffffff<br />#define N 1008<br />int path[N], vis[N];<br />int g[N][N], dist[N][N];<br />void Dijkstra(int n, int beg) {<br /> int i, j, min;<br /> memset(vis, 0, sizeof (vis));<br /> vis[beg] = 1;<br /> for (i = 0; i < n; i++) {<br /> dist[i] = g[beg][i];<br /> path[i] = beg;<br /> }<br /> dist[beg] = 0;<br /> path[beg] = -1; // 樹根的標記<br /> int pre = beg;<br /> for (i = 1; i < n; i++) {<br /> min = INF;<br /> for (j = 0; j < n; j++)<br /> if (vis[j] == 0 && dist[pre] + g[pre][j] < dist[j]) {<br /> dist[j] = dist[pre] + g[pre][j];<br /> path[j] = pre;<br /> }<br /> for (j = 0; j < n; j++)<br /> if (vis[j] == 0 && dist[j] < min) {<br /> min = dist[j];<br /> pre = j;<br /> }<br /> vis[pre] = 1;<br /> }<br />}